Soldering processes are widely used in semiconductor device manufacturing for a variety of purposes, including chip bonding, wire/clip/ribbon bonding, device mounting etc. A variety of solder materials, fluxes, and soldering techniques is available. Soldering methods and soldering substances can have a high impact on cost, yield, performance and reliability of a semiconductor device.
Soldering of aluminum (Al) metallizations requires the application of highly reactive chemicals (fluxes) to remove the highly stable Al2O3 layer on Al metallizations. Such highly reactive chemicals are incompatible with standard semiconductor manufacturing processes. Therefore, soldering on Al surfaces today is limited to applications outside of semiconductor device manufacturing.